Ring guard combination lock



p 1967 v H. c. MILLER ETAL 3,339,383

RING GUARD COMBINATION LOCK Filed June 25, 1965 5 Sheets-Sheet 1 INVENTORS HAMY c: wage 050/9650 041/4 ,5 dOH/V 2. 7404401425 BY g M ATTORNEYS P 1967 H. c. MILLER ETAL 3,339,383

RING GUARD COMBINATION LOCK Filed June 25, 1965 5 Sheets-Sheet 2 za \l q 45 INVENTORS #4470) 6: 41/1159, 60A GQ 0/101 Jam Z. [#0/1/01410/5 BYW TTORNEYS P 5, 1967 H. c. MILLER ETAL 3,339,383

RING GUARD COMBINATION LOCK Filed June 25, 1965 5 Sheets-Sheet 3 INVENTORS HAP/47V c. Mum, GEO/(7G! 0. p404 5 (JO/l/l/ 2. 7904101406 BY I I p 1967 H. c. MILLER ETAL 3,339,383

RING GUARD COMBINATION LOCK Filed June 25, 1965 5 Sheets-Sheet 4 I N VENTORS away a. 44/1 154 a o/ea: a 0,404 6: l/ox/A Z. fl/0MOZ/W/5' BY I P 1967 H. c. MILLER ETAL 3,339,383

RING GUARD COMBINATION LQCK 5 Sheets-Sheet 5 Filed June 25, 1965 |nuulllllk'fillllllllllll Q 'llllllllllllllll JWENTORS 2,5 5% M4 1 M w .20

w VG M22 Aw W HG United States Patent 3,339,383 RING GUARD COMBINATION LOCK Harry C. Miller, George D. Paul, and John Z. Thomolaris, Rochester, N.Y., assignors to Sargent & Greenleaf, Inc., Rochester, N.Y., a corporation of New York Filed June 25, 1965, Ser. No. 467,039 9 Claims. (Cl. 70-333) The present invention relates in general to combination locks and more particularly combination locks having means incorporated therein for resisting surreptitious entry techniques of manipulation thereof by unauthorized persons.

Conventional. locks of the class known as combination locks usually comprise three tumbler wheels which are loosely journalled in coaxial longitudinally spaced relation for rotation within a lock casing on a tubular arbor or tumbler post projecting inwardly of the casing from the front wall thereof. The lock dial, which usually has 100 peripheral calibration marks thereon, is aflixed to a dial spindle which extends through the bore of the tumbier post and has keyed to the inner end thereof a disklike drive cam which is likewise arranged coaxially with :and spaced rearwardly from the tumbler wheels. A drive pin projects forwardly from the drive cam and has a lost motion connection through a conventional fly with the rearmost tumbler wheel to drive the tumbler wheel in selected relation to the drive cam. A similar lost motion connection is provided between each of the successive tumbler wheels so that each of the tumbler wheels may be driven upon selected rotation of the drive cam. Each of the tumbler wheels and the drive cam are provided with a peripheral notch or gating at a selected radial position on the drive cam and tumbler wheels.

A fence lever which is pivotally connected at one end to a reciprocative bolt slidably supported in the lock casing is provided with a depending nose at the opposite end which is designed to ride upon the drive cam periphery and has a bar or fence projecting laterally therefrom in overlying relation with the tumbler peripheries in the tumbler wheels. The position of the fence in relation to the length of the fence lever nose is usually such that the fence is spaced slightly from the tumbler peripheries -when the fence lever nose is riding on the drive cam periphery.

In such a construction, when the tumbler wheel gatings are out of registry with the fence and the dial is turned to the proper position to dispose the drive cam gating below the fence lever nose, the fence lever nose will drop slightly into the drive cam gating until the fence bears upon the tumbler peripheries. The rotation of the dial through small arcs in opposite directions from this position will bring the opposite surfaces of the drive cam gating into contact with the fence lever nose. The points at which the fence lever nose contacts these opposite surfaces at the entrance to the drive cam gating are known as the left and right contact pointso'f the fence lever and may be detected by coordination of the senses of touch and sight by the person manipulating the dial. A variation in the relation and feel of these contact points occurs when one of the tumbler gatings'is positioned beneath the fence, which is distinguishable from the relation and feel of these contact points when all of the tumbler gatings are out of registry with the fence. Because of the fact that the drive cam can be rotated through a sufficient are when the fence is in contact with the tumbler peripheries to reveal the contact points of the fence lever nose, the location of the three tumbler wheel gatings can be determined by unauthorized persons by following a now well known lock manipulation procedure.

Various modifications in combination lock structure have heretofore been resorted to to defeat detection of the lock combination in this manner. Among these is the lock structure disclosed in prior Patents Nos. 2,575,674 and 2,807,954 granted to Harry C. Miller wherein a guard or shielding slide is mounted on the rear face of the drive cam and has a curved end portion conforming to the curvature of the drive cam periphery which normally overlaps the drive cam gating and forms a smooth continuation of the drive cam periphery to support the fence lever nose when the drive cam gating is in registry with the fence lever nose. An inner spindle extends through the dial spindle and is coupled at its inner end to the shielding slide and at its outer end to a knob which is in exposed condition, whereby upon rotation of the knob and inner spindle, the slide may be shifted radially of the drive cam to expose the drive cam gating for reception of the fence lever nose. When the shielding slide is in projected position exposing the drive cam gating to entry of the fence lever nose, stop members on the lock casing are disposed in the path of movement of a portion of the slide to limit rotation of the drive cam to an extent which will prevent detection of contract points for the fence lever nose.

It has been determined, however, that the security of this lock may be adversely affected in time if the portion of the shielding slide which is projected beyond the drive cam periphery becomes worn, as by abrasion against adjacent surfaces of the lock casing. It is possible that the projected end surface of the shielding slide may become worn to a depth equal to the spacing of the fence from the tumbler wheel peripheries when the fence lever nose engages the drive cam periphery. In such a case, the slide may be only partially projected from the position wherein it shields the drive cam gating to lower the fence into contact with the tumbler peripheries and lower the fence lever nose into at least the entrance to the drive cam gating without projecting the slide sufficiently to permit the stop members to limit rotation of the drive cam. In this condition, the dial could be manipulated to permit sensing of the contact points and direction of the combination of the lock.

An object of the present invention, therefore, is the provision of a novel combination lock of the type having a gate shielding member on the drive cam, which will effectively defeat surreptitious detection of the combination of the lock 'by unauthorized persons.

Another object of the present invention is the provision of a combination lock mechanism of the type having a shielding member carried by the drive cam for normally presenting an apparent continuation to the drive cam periphery in the gating zone of the drive cam when the lock is conditioned for tumbler adjusting rotation and which is adjustable to -a gate exposing position, wherein the shielding member is of novel configuration and is associated with the drive cam in a unique manner.

Another object of the present invention is the provision of a novel combination lock mechanism of the type having an adjustable shielding member carried by the drive cam for normally shielding the drive cam gating against entry of the fence lever nose therein when the lock is conditioned for tumbler adjusting rotation and an adjusting member for causing the slide to assume a gate exposing displaced position, wherein the shielding member is of ring shaped configuration having an uninterrupted circular periphery concentric with but of greater diameter than the driving cam pivoted to the latter at an eccentric position to permit selective tilting of the shielding member to a gate exposing position.

Another object of the present invention is the provision of a novel combination lock mechanism of the type having an angularly shiftable guard ring carried eccentrically by the drive cam for normally shielding the drive cam gating against entry of the fence lever nose therein when the lock is conditioned for tumbler adjusting rotation and adjustable to a gate exposing displaced position, wherein an overcenter spring mechanism is directly actuated by an adjusting member and is coupled to the guard ring in a manner to cause delayed action angular displacement of the guard ring to fully displaced position upon a selected degree of movement of the adjusting member and to prevent any movement of the guard ring upon less than said selected degree of movement of the adjusting member.

Another object of the present invention is the provision of a combination lock mechanism of the type described in the preceding paragraphs, wherein novel means are provided to limit the range of arcuate movement of the drive cam and dial when the shielding member is in gate exposing position.

Another object of the present invention is the provision of a combination lock of the type described in any of the preceding paragraphs, wherein novel means are incorporated for selectively and changeably assembling the dial and driving cam spindle in a manner permitting the lock to be installed in either of four quadrature related hands or positions.

Yet, another object of the present invention is the provision of a novel combination lock mechanism of the type having an adjustable shielding member carried by the driving cam selectively adjustable to assume gate shielding and gate exposing positions, wherein the shielding member is rotatable about a pivot point on the drive cam rather than reciprocative rectilinearly to minimize noise incident to operation of the look so as to resist surreptitious detection of the combination by highly sensitive listening devices.

Another object of the present invention is the prevision of a novel combination lock mechanism constructed so as to secure the drive came against rotation by means located internally of the lock casing when the dial and/ or dial ring are chiseled off or otherwise destroyed to defeat unauthorized opening of the lock when this occurs.

Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing showing a preferred embodiment of the invention.

In the drawings:

FIGURE 1 is a vertical section view of one embodiment of a combination lock made in accordance with the present invention, taken along the line 1--1 of FIGURE 2;

FIGURE 2 is a rear elevation of the combination lock with the rear cover removed, and the guard ring in normal, gate-shielding position;

FIGURE 3 is a fragmentary rear elevation similar to FIGURE 2 showing the guard ring in gate exposing position;

FIGURE 4 is an enlarged fragmentary section view of the drive cam and guard ring assembly in gate exposing position, taken along the line 4--4 of FIGURE 3;

FIGURE 5 is an enlarged fragmentary section view of the drive cam and guard ring assembly in gate shielding position, taken along the line 55 of FIGURE 2;

FIGURE 6 is an exploded perspective view of the drive cam and guard ring assembly;

FIGURE 7 is a fragmentary vertical longitudinal section view of the spindle knob and the limit pin and adjacent parts of the drive spindle knob, dial ring and dial also taken along the plane of line 11 of FIGURE 2; showing the limit pin in rearwardly projected position as when the knob is adjusted to dispose the guard ring in gate exposing position;

FIGURE 8 is a fragmentary section view taken along the line 8-8 of FIGURE 7;

FIGURE 9 is a perspective view of the spindle knob;

FIGURE 10 is a fragmentary section view of the dial with the outer spindle hub and spindle knob removed therefrom;

FIGURE 11 is a fragmentary perspective view of the outer spindle and hub assembly; and

FIGURE 12 is a front elevation of the rear cover of the lock casing.

Referring to the drawings, wherein like reference characters designate corresponding parts throughout the several figures, there is illustrated a combination lock, generally indicated by the reference character 20, which is of the general type disclosed in the prior Patents Nos. 2,575,674 and 2,807,954, issued to Harry C. Miller. The combination lock comprises a substantially rectangular lock casing 21 having a hollow boss 22 projecting inwardly from the front wall thereof. Secured to the outer face of the door concentric with the axis of the hollow boss 22 is a dial ring 24, here shown as having a cylindrical shield 24a surrounding and shielding from view the major portion of the periphery of dial 25, but interrupted by a sight opening of suitable arcuate extent.

Rotatably supported within the hollow boss 22 is an axially bored drive spindle 26 threaded at its outermost end to the dial 25 having an integral knob 25a associated therewith and supported to rotate within the recess of the dial ring 24. The inner end of the drive spindle 26 is threaded to receive an internally threaded portion of a tubular boss 27 projecting from a driving cam 28, the driving cam being keyed to the driving spindle 26 by means of a suitable spline key 26.

A plurality of tumblers, generally indicated by the reference characters 29, 30 and 31 are supported to rotate freely upon the portion of the hollow boss projecting within the lock casing 21, each of the tumblers being of the conventional type designed to be changed by means of a combination resetting key to vary the combination of the lock, and to this end comprising an inner hub on each of which are supported a pair of annular disks having a tumbler gate or recess 32 therein. The outer annular disks are selectively locked against rotation relative to their supporting hubs by means of conventional locking arms carried by the annular disks and engaging peripheral serrations or teeth on the hubs to hold the annular disks in fixed position.

Conventional fiys 33 consisting of annular rings having an outwardly radiating projection thereon are provided between the outermost and intermediate tumblers 31 and 30 and between the intermediate and innermost tumblers 30 and 29 to rotate in annular recesses provided in the adjacent faces of the inner hubs of the tumblers 31 and 30. The radial projections of the flys engage stops on the adjacent tumblers to provide a lost motion driving connection between the tumblers operatively associated with each fly. The innermost tumbler 29 is provided with a special fly 34 having an annular ring to surround and ride freely on the hollow boss 22 and an outwardly radiating projection terminating in a triangular tip having inclined converging faces producing a cam surface, the faces being inclined, in the preferred embodiment, at external angles of degrees each with the medial radial plane of the projection.

The lock is provided with a bolt 35 which is adapted to slide in a suitable guideway formed in one wall of the casing 21, the bolt 35 being operated by a fence lever 36 pivotally attached thereto by means of a screw 37. The fence lever 36 is continuously resiliently urged toward the tumblers by means of a suitable spring 38 and is provided with a laterally projecting bar 39, commonly referred to as a fence, which projects along an axis parallel to the axis of the drive spindle 26 and overlies the peripheries of all the tumblers 29, 30 and 31. The fence 39 is adapted to be received in the gates 32 of the tumblers when the tumbler gates are disposed in registry upon operation of the dial knob 25a to establish the combination. The downward rotation of the fence lever 36 when the fence enters the gates permits the shoulder 40 on the free end of the fence lever 36 to fall free of the depending boss 41 on the top wall of the lock casing 21 and permit the fence lever to be shifted laterally beyond the boss 41 to withdraw the bolt 35 from its projected position.

The driving cam 28 is provided with a driving cam gate 42 adapted to receive the nose 43 of the fence lever 36. As will be observed from the illustration of the driving cam 28 in FIGURE 2, the driving cam gate 42 has a pair of diverging Walls, one forming an inclined slightly convex wall for controlling the movement of the fence lever nose 43 into the driving cam gate and therefore the speed of approach of the fence 39 toward the tumbler peripheries, and the other wall forming a shoulder for cooperating with a complementary shoulder on the fence lever nose 43 by which the fence lever 36 is shifted to retract the bolt 35 upon rotation of the driving cam in a counterclockwise direction as viewed in FIGURE 2.

The drive cam 28 supports a guard ring 45 on the rear face thereof having an uninterrupted cylindrical periphery 46 which is slightly larger in diameter than the drive cam and a large central opening 47. The guard ring 45 is pivotally carried on the rear face of the drive cam by means of a pivot pin 48 extending through the guard ring 45 into a drilled hole and rivetted in the drive cam located eccentrically of the center of rotation of the drive cam, for example near the pheriphery thereof. The guard ring 45 carries a drive pin 49 which projects both forwardly and rearwardly thereof, having a triangular tip 49a in the portion thereof projecting toward the tumblers forming inclined cam faces to impart rotation to fly 34 upon rotation of drive cam when the guard ring 45 is in shielding position and adapted to cooperate with the cam faces on the projection of the rearmost fly 34 to cam the fly 34 in either direction about its axis of rotation when the drive pin 49 is shifted radially inwardly toward the tumbler axis upon adjustment of the guard ring from non-shielding to shielding position and prevent jamming of the guard ring in non-shielding position. The drive cam 28 is suitably recessed as indicated at 50 to receive the triangular tip portion 49a of the drive pin when the guard ring 45 is in shielding position centered with respect to the axis of the drive cam and tumblers, the surfaces of the recess 50 serving as stop shoulders to accurately locate the drive pin and guard ring in this centered position.

The guard ring 45 is resiliently biased to either its shielding or non-shielding positions by an overcenter spring 51, depending on the position of the spring. One end of the spring 51 is fitted into an ec-centrically located aperture 52 in the guard ring 45 while the other end of the spring is turned about a spring anchor pin 53 carried at an eccentric location on an actuating cam 54 which rotates concentrically with the axis of the drive cam 28 within the opening 47 of the guard ring 45 and is fixed on-the rearmost end of an inner spindle 55 projecting through and rotatable in the axial bore in the drive spindle 26. The actuating cam 54 is limited in its range of angular movement by radial shoulders 56 thereon disposed to abut portions of the spline key 26' projecting rearwa-rdly of the drive cam 28. The forwardmost end of the inner spindle 55 is fixed into an auxiliary knob 57 having a cylindrical body portion nested rotatably in a cylindrical forwardly opening cavity in the knob portion 25a of unitary dial and knob member 25. The auxiliary knob 57 may be releasably held in the cavity by any conventional means, such as pins radially projecting from the knob 57 into an annular groove in the wall of the cavity having axial transitions to the front end of the cavity for insertion and withdrawal of the knob 57, or by a split ring interfitting in aligned grooves in the cavity wall and the knob, or by set screws or the like. The auxiliary knob 57 preferably has an elongated projection on its front face to facilitate manipulation thereof, and is provided with an arcuate recess bounded by cam surfaces 5 8, in its rear face coactive with an axially movable limit pin 59 slidably supported in the hole 60 in dial 25 and resiliently biased toward the auxiliary knob 57 by spring 61 6 compressed between the head of pin 59 and the surface of dial 25 bounding the hole 60.

The limit pin 59 actuated by the auxiliary knob 57 serves to restrict the range of rotation of the dial 25 which is permitted when the knob 57 is positioned to dispose the guard ring 45 in non-shielding position, the stationary dial ring 24 having a forwardly opening arcuate slot 62 aligned with the path of rotation of the limit pin 59 to receive the rearmost end thereof when the auxiliary knob 57 has been rotated to a suflicient degree to bring the higher region of the inclined ramp portion 58a of cam surfaces 58 into contact with the limit pin 59 and maintain the limit pin so projected into the slot 62 over the arcuate range of the rearmost fiat portion 58b of cam surfaces 58. With the above described components, as the auxiliary knob 57 and inner spindle 55 are rotated in a counterclockwise direction as viewed in FIGURE 3 through the range permitted by the limit pin 59 and slot 62, the spring anchor pin 53 is shifted about the axis of the drive cam through an a-rcuate path approaching the location of the end of spring 51 fitted in opening 52 in the guard ring 45, causing the spring 51 to become progressively tensioned by forcing the opposite ends thereof toward each other, thus storing energy in the spring. When the anchor pin 53 then passes beyond the end of spring 51 in opening 52, the reaction force of the spring 51 is shifted to a new direction and is released to drive the guard ring in an arcuate path about its pivot pin 48 to projected or non-shielding position exposing the driving cam gate 42 to receive the fence lever nose 43. Since there is no force component of the spring 51 acting on the guard ring in an opening direction until the anchor pin 53 passes beyond the end of spring 51 in opening 52, projection of the guard ring to non-shielding position is prevented until sufiicient energy is stored in the spring 51 to insure full projection of the guard ring to its limit position. The guard ring 45 is limited in its opening movement by abutment of the bounding surface of opening 47 therein with the spring anchor pin 53 when the guard ring reaches the desired fully open or non-shielding position.

Efiorts are sometimes made to gain unauthorized entry to a lock by chiselling off the dial, and dial ring, and manipulating the thus exposed dial spindle. The present lock is provided with means internally of the lock casing to prevent throwing of the guard ring to non-shielding position except when the drive cam is at a preselected angular position and to limit rotation of the driving cam when the guard ring is so thrown, even though the restriction imposed by the limit pin 59 and slot 62 be destroyed. To this end, the drive pin 49 has a cylindrical rearw-ardly projecting portion 49b, and the rear cover 65 for the lock casing has a circular groove 66 therein which is concen-' trio with the axis of the drive cam and is aligned with the path of the drive pin 49 when the guard ring 45 is in normal shielding position. A transition groove 67 communicates with the circular groove 66 atthe circumfer ential position occupied by the drive pin 49 when the dial is adjusted to the preselected angular position at which the auxiliary knob 57 should be operated to project the guard ring to non-shielding position, and extends along the path which the drive pin traverses when the'guard ring is shifted from shielding to non-shielding position. The transition groove 67 terminates in an arcuate portion 68 which is concentric with the axis of the drive cam 28 at a radial distance corresponding to that of the drive pin when the guard ring is in non-shielding position and of a circumferential range corresponding to that of slot 62. Thus, even though the restriction provided by limit pin 59 and slot 62 be destroyed, the internal restriction imposed by the drive pin 49 and grooves 66, 67 and 68 will be present.

To render the lock mechanism readily adaptable to any of the four customary hands of operation, the drive spindle 26 is provided at its forward end with an enlarged diameter spindle hub 70 having four quadrature-related U-shaped sockets 71 in its periphery. The inner end of the cavity in the dial 25 is likewise provided with three similarly shaped bosses or lugs 72 positioned 90 apart to fit into any three of the sockets 71, the fourth socket 71 providing passage for the head of the limit pin 59. One of the bosses 72 may, if desired, be provided with an opening to receive a screw, to permit securing a retaining ring (not shown) against the front faces of the bosses to retain the spindle hub 70 in interlocked relation with the dial.

The combination lock of the above-described construction is manipulated in the conventional manner to position the tumbler gates in registry with each other and in alignment with the fence 39 by rotating the dial knob 25a and dial 25 three complete revolutions in a counterclockwise direction to bring a preselected dial marking in alignment with the index mark on the dial ring 24, then two complete turns in a clockwise direction to bring another dial marking into alignment with the fixed index mark, and then another complete revolution in a counterclockwise direction to align the third dial number with the index mark. During this manipulation of the dial knob and dial, the guard ring 45 is in the position illustrated in FIGURE 2 of the drawing wherein the uninterrupted periphery 46 of the guard ring 45 supports the fence lever nose 43 out of contact with the driving cam 28. The forwardly projecting portion of the drive pin 49 under this condition of the lock engages the projection of the special fly 34 to impart lost motion drive to the rearmost tumbler 29, the intermediate and for-- ward fly 33 being picked up by pins projecting from the rear and intermediate tumblers 29 and 30 upon subsequent complete revolutions of the driving cam 28. When the tumbler gates have been thus aligned with the fence 39, the dial 25 is rotated in a clockwise direction to bring the zero mark into alignment with a fixed index mark on the dial ring 24. In this position the rearwardly projecting portion of the drive pin 49 on the guard ring 45 is aligned radially with the transition groove 67 in the rear cover 65, the limit pin 59 in the dial 25 is aligned with one end portion of the slot 62 in dial ring 24, and the driving cam gate 42 is disposed immediately below the fence lever nose 43. The auxiliary knob 57 is then rotated through a selected range, rotating the inner spindle 55 and actuating cam 54 in an appropriate direction to shift the guard ring 45 about the pivot pin 48 in an arcuate path toward the position illustrated in FIGURE 3. When the anchor pin 53 on the actuating cam 54 passes clockwise beneath the end of spring 51 in hole 52 of guard ring 45 as previously described, the angular position of the spring 51 which has been highly tensioned during the relative approaching movement of the ends thereof is shifted so as to exert a counterclockwise rotating force on the guard ring about its pin 48, the stored energy in the spring 51 being sufficient to fully project the guard ring 45 to the non-shielding position illustrated in FIGURE 3. If the tumbler gates 32 were aligned in position to receive the fence 39, the fence lever will then fall under the force of the spring 38 to seat the fence lever nose 43 in the driving cam gate 42.

During such rotation of the auxiliary knob 57 to shift the guard ring 45 to open or non-shielding position, the head or forward end of the limit pin 59 is engaged progressively by the ramp portion 58a. and then the flat portion 58b of the cam surfaced recess 58 to drive the limit pin 59 axially rearwardly against the force of its spring 61 into the slot 62 in dial ring 24 adjacent one end of the slot. The dial 25 can then be rotated in a counterclockwise direction as viewed in FIGURE 3 through the limited range permitted by the slot 62, which is just sufficient to effect retraction of the bolt 35 through the action of the driving cam gate 42 on the fence lever nose 43. It will be observed that the arcuate groove portion 68 in the rear cover 65 which receives the rearwardly projecting portion of the drive pin 49 in the non-shielding position of the guard ring 45 is of similar arcuate range to the slot 62 to also limit rotation of the driving cam in this condition of the lock to this range.

To reclose the lock, the operator need merely rotate the dial in the reverse direction to bring the drive pin 49 on the guard ring 45 into alignment with the transition groove portion 67 and then rotate the auxiliary knob 57 in the reverse direction, which rotates the actuating cam 54 and returns the guard ring 45 to its normal position concentric with the drive cam 28, the spring 51 being shifted in a reverse relation by the movement of the actuating cam 54 to return the guard ring 45 to its normal position.

It will be appreciated that the combination lock construction hereinabove described may be used with dials and escutcheon plates or dial rings of conventional configuration rather than the cylindrical graduated dial periphery and annular shielding surrounded on the dial ring herein disclosed.

While but one preferred example of the present invention has been particularly shown and described, it is apparent that various modifications may be made therein within the spirit and scope of the invention, and it is desired, therefore, that only such limitations be placed on the invention as are imposed by the prior art and set forth in the appended claims.

What is claimed is:

1. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith; the improvement comprising shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring having an uninterrupted cylindrical periphery of slightly larger diameter than said driving cam pivotally supported at an eccentric point on the latter for arcuate movement from a normal concentric position relative to the driving cam supporting said nose against entry of the fence lever nose in said gate to a displaced position exposing said gate to receive said nose, a movable actuating member adjacent said driving cam, manipulating means coupled to said actuating member for moving the latter relative to said guard ring over a preselected range of movement, and spring means coupled to said actuating member and to said ring guard to be actuated by movement of the actuating member to store up energy during movement of the actuating member thereof toward a selected intermediate position in said range of movement and be shifted to a direction upon passage of said intermediate position to expend the stored up energy on said guard ring to drive the latter fully to said displaced position.

2. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith; the improvement comprising shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring of greater diameter than said driving cam pivoted eccentrically on said driving cam for arcuate movement from a normal shielding position concentric with said driving cam to a non-shielding position displaced angularly from said concentric relation exposing the driving cam gate to receive the fence lever nose, a rotatable actuating member adjacent the axis of said driving cam, manipulating means coupled to said actuating member for rotating the latter relative to said guard ring over a preselected range of movement, and spring means coupled to said actuating member and to said guard ring to be actuated by rotation of the actuating member to undergo stressing during movement thereof toward a selected in-. termediate position in said range of movement and be shifted to a direction upon passage of said intermediate position to expend the return force of the spring means on said shielding slide to drive the latter fully to said non-shielding position.

3. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, 2. bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses When the latter are adjusted in registry therewith; the improvement comprising shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring of greater diameter than said driving cam pivoted to the latter at a point eccentric to the axis of rotation of the driving cam for arcuate movement from a normal shielding position concentric with the driving cam to a non-shielding position displaced angularly from said concentric relation exposing the driving cam gate to receive the fence lever nose, an externally accessible rotatable member having an actuating member thereon adjacent said driving cam and guard ring movable relative to the guard ring over a preselected angular range of movement, and spring means coupled at one end to said actuating member and at the other end to said guard ring to be actuated by rotation of the actuating member to undergo compression during movement thereof toward a selected intermediate position in said angular range of movement and be shifted to a direction upon passage of said intermediate position to expend the return force of the spring means to drive said guard ring about its pivot point fully to said non-shielding position.

4. In a combination lock, the combination defined in claim 3 wherein said lock includes a drive spindle fixed to said driving cam having an externally exposed, unitary dial and dial knob fixed on one end thereof, said dial knob having a forwardly opening cylindrical cavity therein, a dial ring having central bearing means for journaling said drive spindle, a limit pin supported by said dial having a follower end extending into said cavity and a second end projecting toward said dial ring, said dial ring having an arcuate slot concentric with said spindle for receiving said second end of said pin and limiting arcuate movement of said pin and dial through a selected angular range appropriate to retract the bolt, and said externally accessible rotatable member including an auxiliary knob rotatably disposed in said cavity, having cam surfaces engageable with said follower end of said limit pin for normally locating said limit pin out of engagement with said slot and for projecting said second end of said limit pin into said slot when said auxiliary knob is positioned to dispose said guard ring in non-shielding position.

5. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler Wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith; the improvement comprising shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring of greater diameter than said driving cam pivoted to the latter at a point eccentric to the axis of rotation of the driving cam for arcuate movement from a normal shielding position concentric with the driving cam to a non-shielding position displaced angularly from said concentric relation exposing the driving c-am gate to receive the fence lever nose, an externally accessible rotatable member having an actuating member thereon adjacent said driving cam and guard ring movable relative to the guard ring over a preselected angular range of movement, spring means coupled at one end to said actuating member and at the other end to said guard ring to be actuated by rotation of the actuating member to undergo compression during movement thereof toward a selected intermediate position in said angular range of movement and be shifted to a direction upon passage of said intermediate position to expend the return force of the spring means to drive said guard ring about its pivot point fully to said non-shielding position, a rigid finger projecting rearwardly from said guard ring, and a casing for said lock having a guide groove therein for receiving said finger and accommodating arcuate movement of said guard ring between said shielding and non-shielding posi tions at only one selected angular position of said driving cam and limited rotary movement of the driving cam when the guard ring is displaced fully to its non-shielding position.

6. In a combination lock, the combination defined in claim 5 wherein said lock includes a drive spindle fixed to said driving cam having an externally exposed, unitary dial and dial knob fixed on one end thereof, said dial knob having a forwardly opening cylindrical cavity therein, a dial ring having central bearing means for journalling said drive spindle, a limit pin supported by said dial having a follower end extending into said cavity and a second end projecting toward said dial ring, said dial ring having an arcuate slot concentric with said spindle for receiving said second end of said pin and limiting arcuate movement of said pin and dial through a selected angular range appropriate to retract the bolt, and said externally accessible rotatable member including an auxiliary knob rotatably disposed in said cavity having cam surfaces engageable with said follower end of said limit pin for normally locating said limit pin out of engagement with said slot and for projecting said second end of said limit pin into said slot when said auxiliary knob is positioned to displose said guard ring in non-shielding position.

7. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith; the improvement comprising shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring of greater diameter than said driving cam pivotally connected eccentrically to said driving cam for arcuate movement from a normal shielding position concentric with said driving cam to a non-shielding position displaced angularly from said concentric relation exposing the driving cam gate to receive the fence lever nose, a rotatable actuating cam in the central opening of said ring and against said driving cam, spindle means operable from externally of the lock and coupled to said actuating cam for rotating the same relative to the driving cam over a preselected range of angular movement, and a spring member having opposite ends anchored to said guard ring and actuating cam respectively located to effect compression of said spring member during movement of said actuating cam toward a selected intermediate position in said range of angular movement and shift said spring member upon passage of said intermediate position to a direction whereby the return force of the spring member drives said guard ring fully to non-shielding position about its pivotal connection to the driving cam.

8. A combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a drive spindle fixed to said driving cam having an externally exposed dial fixed to one end thereof, a dial ring having a central spindle bearing journaling said drive spindle, a bolt, a fence lever pivotally connected to said bolt having a nose for engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said v driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith, shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including a shielding member supported on said driving cam for movement from a normal shielding position to a non-shielding position relative to the driving cam gate, a rotatable actuating member adjacent said shielding member, an actuating spindle extending coaxially through said drive spindle having one end fixed to said actuating member and an externally exposed knob fixed on the other end of sa1d actuating spindle adjacent the center of said dial for rotating the actuating member relative to the driving cam over a preselected range of movement, spring means coupled to said shielding member and actuating member to store up energy during movement of said actuating member toward a selected intermediate position in said range of movement and be shifted to a direction upon passage of said intermediate position to expend the stored up energy on said shielding member to drive the latter fully to non-shielding position, a limit pin supported by sa1d dial for axial movement parallel to said actuating spindle between said dial ring and said knob, said dial ring having an arcuate slot concentric with said spindle for receiving an end of said limit pin and limiting the arcuate movement of the same through a selected range of dial rotation appropriate to retract the bolt, and cam surfaces on said knob for normally locating said limit pin spaced from said slot and for projecting the limit pin into said slot during adjustment of said knob to a position disposing said shielding member at said non-shielding position.

9. In a combination lock having a plurality of selectively adjustable, peripherally recessed tumbler wheels, a rotatable driving cam for adjusting said tumbler wheels, a drive spindle fixed to said driving cam having an externally exposed dial fixed to one end thereof, a dial ring having a central spindle bearing journaling said drive spindle, a bolt, a fence lever pivotally connected to said bolt having a nose for selectively engaging the periphery of said driving cam and a laterally extending fence transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate for receiving said fence lever nose to permit said fence to enter the tumbler recesses when the latter are adjusted in registry therewith, shielding means to selectively shield said driving cam gate against entry of the fence lever nose therein including an annular guard ring of greater diameter than said driving cam pivotally connected eccentrically to said driving cam for arcuate movement from a normal shielding position concentric with said driving cam to a nonshielding position displaced angularly from said concentric relation exposing the driving cam gate to receive the fence lever nose, a rotatable actuating cam in the central opening of said ring and against said driving cam, spindle means operable from externally of the lock and coupled to said actuating cam for rotating the same relative to the driving cam over a preselected range of angular movement, a spring member having opposite ends anchored to said guard ring and actuating cam respectively located to effect compression of said spring member during movement of said actuating cam toward a selected intermediate position in said range of angular movement and shift said spring member upon passage of said intermediate position to a direction whereby the return force of the spring member drives said guird ring fully to non-shielding position about its pivotal connection to the driving cam, an externally exposed knob on said spindle means at the center of said dial rotatable relative to the latter, an axially movable limit pin supported by said dial for rotation therewith, said dial ring having an arcuate slot for receiving an end of said limit pin and limiting the arcuate movement of the same through a selected range of dial rotation appropriate to retract the bolt, means biasing said pin toward said knob, and cam surfaces on said knob normally locating said limit pin outwardly of said slot and forcing the limit pin into said slot during rotation of the knob adjusting said guard ring to non-shielding position.

References Cited UNITED STATES PATENTS 2,575,674 11/1951 Miller -333 2,807,954 10/1957 Miller 70333 3,170,316 2/1965 Miller et al 70333 BOBBY R. GAY, Primary Examiner. 

1. IN A COMBINATION LOCK HAVING A PLURALITY OF SELECTIVELY ADJUSTABLE, PERIPHERALLY RECESSED TUMBLER WHEELS, A ROTATABLE DRIVING CAM FOR ADJUSTING SAID TUMBLER WHEELS, A BOLT, A FENCE LEVER PIVOTALLY CONNECTED TO SAID BOLT HAVING A NOSE FOR SELECTIVELY ENGAGING THE PERIPHERY OF SAID DRIVING CAM AND A LATERALLY EXTENDING FENCE TRANSVERSELY OVERLYING THE PERIPHERIES OF SAID TUMBLER WHEELS, SAID DRIVING CAM HAVING A PERIPHERAL GATE FOR RECEIVING SAID FENCE LEVER NOSE TO PERMIT SAID FENCE TO ENTER THE TUMBLER RECESSES WHEN THE LATTER ARE ADJUSTED IN REGISTRY THEREWITH; THE IMPROVEMENT COMPRISING SHIELDING MEANS TO SELECTIVELY SHIELD SAID DRIVING CAM GATE AGAINST ENTRY OF THE FENCE LEVER NOSE THEREIN INCLUDING AN ANNULAR GUARD RING HAVING AN UNINTERRUPTED CYLINDRICAL PERIPHERY OF SLIGHTLY LARGER DIAMETER THAN SAID DRIVING CAM PIVOTALLY SUPPORTED AT AN ECCENTRIC POINT ON THE LATTER FOR ARCUATE MOVEMENT FROM A NORMAL CONCENTRIC POSITION RELATIVE TO THE DRIVING CAM SUPPORTING SAID NOSE AGAINST ENTRY OF THE FENCE LEVER NOSE IN SAID GATE TO A DISPLACED POSITION EXPOSING SAID GATE TO RECEIVE SAID NOSE, A MOVABLE ACTUATING MEMBER ADJACENT SAID DRIVING CAM, MANIPULATING MEANS COUPLED TO SAID ACTUATING MEMBER FOR MOVING THE LATTER RELATIVE TO SAID GUARD RING OVER A PRESELECTED RANGE OF MOVEMENT, AND SPRING MEANS COUPLED TO SAID ACTUATING MEMBER AND TO SAID RING GUARD TO BE ACTUATED BY MOVEMENT OF THE ACUTATING MEMBER TO STORE UP ENERGY DURING MOVEMENT OF THE ACTUATING MEMBER THEREOF TOWARD A SELECTED INTERMEDIATE POSITION IN SAID RANGE OF MOVEMENT AND BE SHIFTED TO A DIRECTION UPON PASSAGE OF SAID INTERMEDIATE POSITION TO EXPEND THE STORED UP ENERGY ON SAID GUARD RING TO DRIVE THE LATTER FULLY TO SAID DISPLACED POSITION. 